Hydrangea transplanting in heat

We planted a pair of Hydrangea in a facing east inside corner. It gets a lot of direct sunlight until after about 10am. It has not done well and I would like to move them to a shady spot. Is this a bad time to try to transplant them. It's in the mid 90s for highs. They are about 18" tall.

If you like their current spot, try making a cover over them, watering them at least daily. They should make it. I am rooting some Hydrageacuttings and to protect them i moved a picnic table over them to provide shade. They are doing well and later this summer i will remove the cover after the roots develop more. Hope this helps!

What kind of Hydrangea? If big leaf (Macrophylla) then I would probably move them to a big pot or a very moist, shady spot for summer. I moved two stressed big leaf hydrangeas a week or two ago and they look better already. Other types (paniculata and oakleaf) might just need supplemental water every week for at least a year or two (always a good idea on new shrubs and trees anyway).

Q. What kind of hydrangea is it? The one in the picture appears to be a hydrangea macrophylla (aka, Bigleaf Hydrangea, French Hydrangea or Hortensia). The type of bloom in the picture makes many call the bloom a mophead so, the shrub is sometimes called a mophead hydrangea too.

Q. Is this a bad time to try to transplant them? I could not tell if this shrub was just planted now or this year but, I will assume that they were “recently planted”.

Now -in the middle of the summer in Texas- is a bad time to plant or transplant a typically water hungry hydrangea. But, you can leave them there or transplant them too. Just be ready as things will only get hotter.... and our hottest months have not arrived. If they are transplanted, they may probably "pout a little". How about temporarily transplanting them into, say, pots?; then transplant them from the pots to a permanent location in the Fall… provided you give TLC (water) until cooler temps arrive in the Fall.

but would I transplant them or would I recommend transplanting them because they are getting sun until 10am? Well, unless there are other issues, that does not appear necessary. They will continue having these wilting fits anyway.

Newly planted hydrangeas generally suffer from heat stress once temperatures are typically above 85F in the summer months. In Texas, that happens in mid May and lasts well into September. The problem is a combination of factors: (1) being in Texas during the summer, (2) those big ole’ leaves, (3) harsh sunlight, (4) high summer temperatures (90-110s), (5) slow and fast drying summer winds, (6) a root system that was recently pruned (it was pruned to fit into the plastic pots in which the plant was sold) and (7) not getting evenly moist soil.

Like I said, getting sun until 10am sounds just fine. They are not going to die if properly watered. I currently have several macrophyllas, serratas, arborescens, oakleafs and paniculatas growing in either morning sun only, dappled sun or in “bright” full shade.

The ones in "morning sun only" get shade starting at 11am-12pm (a tad more sun than yours) and the rest get shade either before 10am or always (which is more shade than yours). They all wilt when it is hot. Even the ones in "bright" full shade.

The problem that we all have is that, in the summer or in windy days, the root system of a recently planted hydrangea cannot absorb water as fast as the leaves lose moisture. Water being absorbed is not equal to the water lost via the leaves. This creates a pressure differential and the leaves wilt. It is also a form of defense mechanism that happens to reduce the surface area of leaves in direct contact with sunlight....Wilting is something that helps them, albeit it does look aaaawful sometimes, doesn't it?

Can you help them? Yes, I too have used umbrellas, outdoor chairs and even a weird contraption made with branches and a cardboard top! Ha! Move them? Eh, I would not.

That contraption I built was needed when a hailstorm broke the branches of a Crape Myrtle that was shading the hydrangea. When the hydrangea started getting too much sun, these were the signs: leaves in direct contact with the sun turned all yellow, including the leaf veins and, the other leaves not in contact with the sun? Well, those stayed dark green. So it looked like a bush with mostly yellow outer leaves whose inner leaves were green. It reminded me of Christmas lights (but just yellow and green in this case) when I saw that. Then I built the contraption. It helped but it was a pain to upkeep as winds toppled the thing often.

When a newly planted hydrangea gets too much sun and reacts like that, you usually need to transplant it elsewhere. Directly to its permanent location or temporarily into a pot. I left my hydrangea there because my contraption was giving it temporary respite from the sun and I knew that Crape Myrtles were aggressive growers and would soon rebuild the branches that were lost to the storm.

But macrophyllas usually fix the wilting themselves at night, all on their own... provided that the soil has sufficient moisture. So, no need to water them every single time that you see them wilted... provided that they have enough soil moisture.

If they do not have enough soil moisture? They will appear wilted in the morning for sure, at which time you can water them (say, one gallon of water). Of course, if you happen to observe an unusually extreme looking wilting episode, give the plant 1 gallon of water immediately. In future years though, this should occur less.

A recently planted hydrangea needs about 1 gallon of water in the Spring. Keep them well mulched year around, about 2-4" past the drip line, to minimize losing soil moisture. When temperatures start to mostly stay above 85F in May-ish, tweak the sprinkler settings to increase the amount of water per plant from 1g to 1.5 to 2 gallons. When temperatures start to stay above 95-100F, increase the amount of water again to 2 to 2.5 gallons each time you water. Feel free to tweak the number of gallons mentioned above to compensate for soil types (e.g., use 50% more water if your soil is sandy), unusual weather and for future plant growth.

Water the soil from the crown outwards (in all directions) and never water the leaves in order to control the cercospora leaf spot that your leaves currently have and in order to prevent future cases of powdery mildew. If the sprinkler gets the leaves wet, water them close to sunrise.

In the Fall, when temperatures are mostly below 100-95F, reduce watering back to 1.5g to 2g per plant. When temperatures are usually below 85F, reduce waterings back to Spring levels (about 1 gallon). Once the shrubs go dormant in late November or in December, you can decrease waterings based on local rains (I usually reduce waterings to once a week or once every two weeks).

Resume Spring levels of waterings when you observe leaf out. If any of your hydrangeas stays evergreen, you may want to test the soil with the finger method sometimes during winter just to make sure that the roots do not get too dry.

To determine if you need to water, use the finger method: early in the mornings, insert a finger into the soil to a depth of 4” to determine of the soil feels dry, moist or wet/soggy. Hydrangeas have small fibrous roots in the top 4” that help absorb water and you need to make sure these do not dry out in the summer. If the soil feels dry or almost dry, water the soil. For 2-3 weeks daily, use the finger method. And each time that you water, make a note in a wall calendar.

After 2-3 weeks, review the information on the wall calendar. Try to average out how often you were watering. Let’s say that you watered 1 gallon per plant every 3 days on average. Then, set the sprinkler or drip irrigation to deliver 1 gallon of water every 3 days. If temperatures go up or down by 10-15 degrees and stay there most of the time, try using the finger method again for 2-3 weeks to see if you need to tweak things.

Make notes of watering habits so you can refer to them next year. Things like "I increased water from x to y on day xyz". Save that info in a wall calendar or as a reminder in a computer calendar.

So why not just water them over and over? If you have soil that drains very well, you could water them a lot, even multiple times a day. This is what some people do when the hydrangeas are in containers/pots. This is what some city gardens do too. So why not? Well, when planted in the ground, all this watering might cause root rot if the soils does not drain very well, the roots stay in soggy soil and you do not notice.

So why not transplant it to a place that just gets an hour of sun? Because it is not showing signs of getting too much sun. It is just hot. Like I said before, I have some hydrangeas that get no direct sun. They are in "bright" full shade. And they bloom just as well as the others but, they will still wilt like yours when it is hot. They still wilt when the others do. So wilting is not a sign of getting too much sun. The quick loss of soil moisture through the leaves still happens to my hydrangeas. In our hot and dry summers, it does not take much for a 5mph dry summer wind to make them wilt. But feel free to help them (chairs, etc) in their first few summers. Or let them wilt. They should develop a bigger root system and become established in about 1-3 years.

In future years, they will wilt less. But note that I did not say that they will never wilt. I have a 20+ year old hydrangea that always wilts when the temps here get to the mid 90s or beyond to the 110s. Oakleaf hydrangeas are more drought tolerant than macrophyllas though so they wilt less even though their leaves are much bigger.

Does this help? Luis

This message was edited Jul 10, 2019 5:48 AM

Bit leaf hydrangeas are going to wilt due to heat and loss of moisture. Shade will help plus keeping the soil moist at all times (not soggy wet).

Here is one of the hydrangeas I dug up in late June. This one is Pistachio and this was 4 days ago. I keep it in filtered light and water it every 2 to 3 days.

Here are two more from the same bush but one is pretty wilted - perhaps doesn't have the root system to support the leaves. I still expect it to recover and grow very well next year. The main thing is keeping it alive this year.

I don't know the name of the 3rd one but it was a cutting from either one of mine or given to me from a friend. I kept it in a pot for two years and planted it in the ground last year.

The fourth one is of two I have on the other side of the fence so watering is harder to do. One is LA Dreaming and the other one is Purple Princess but to me they look the same.

Last one is Penny Mac (gets hot afternoon sun for 2 to 4 hours every day) which needs watering almost every day or two due to the heat. The blooms are fading now and the leaves are spotting (UGLY) but it has done its job for the year.

Thanks Luis for the great comments. I'll work carefully to follow your pointers and, for now keep them where they are. We planted them last year late summer and they did fine until this year when it got hot. I'm sure that we were not watering enough since the soil is really friable and sandy mixed with some potting soil. Thanks again.

Hydrangeas are a poor choice for your climate under any circumstances.

Read Luis's post about what it takes to raise hydrangeas in Texas.

Yet Luis grows a lot of hydrangeas in Texas (I assume that since he writes a lot about hydrangeas). I see Willis, TX is near Houston (about 50 miles) and I bet they grow lots of hydrangeas in these areas.

http://houstonlifestyles.com/hydrangeas/

https://plantsforallseasons.com/growing-hydrangeas-in-texas/

https://www.chron.com/life/gardening/article/Several-hydrangeas-do-well-in-Houston-1595718.php